Optix prime acceleration disables Cuda
mumia76
Posts: 146
If I enable optix prime acceleration the rendering initialization becomes extremely slow. Basically just sitting there for 2 minutes without doing anything. Then it starts rendering on the CPU ONLY. GPU usage remains at 0% trough the entire process and the rendering is as slow as you'd expect it from a CPU only render. Despite the assets being copied to gpu memory (I observe with GPUShark)
It only happens with specific scenes. What could cause this? I've tried with both the latest stable 4.10, and th latest 4.11 beta version. They show the same symptoms.
Interactive rendering still works fine with Iray, this only happens during actual production rendering.
Any ideas?
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Comments
Probably the scene plus whatever memory optix acceleration uses exceeds your available VRAM.
It's a simple scene, doesn't even get near VRAM capacity. I've seen what it looks like when VRAM runs out, this is not that.
Make sure. Until you know for sure that has to be the baseline assumption.
Optix is an Nvidia thing IIRC, so it has to be something else. Maybe the checkbox is wired wrong, or maybe Windows is misinterpreting the command. I went through something similar recently where selecting a GTX980 4GB for rendering (the main GPU had too little free VRAM) dumped to the CPU, and that was a single G2F wearing a hooded cloak with dForce on it and nothing else in the scene, not even the background loaded, at a 1920x1080 resolution like I always do.
Just prior, I was rendering single-figures wearing boots, corsets, gloves, and hair, and all with Iray materials, on the same GPU at a full 18" wide by 74" tall for printing wall posters, and it did just fine, and in under an hour.
Roll back your display drivers using DDU (Display Driver Uninstaller) to clean them out completely. Reboot into Safe Mode (hold Shift as you click Restart) so it can really get in there and clean things up. Then install a previous driver from the 389 range.
Your problem, unless the failure was consistently reproducible after a reboot, sounds like the very well known memory leak.
I certainly hope you didn't go through all that for something that could have been solved by a reboot?
Just don't use Optix.
Actually, one needs to be careful about making any assumptions; so often symptoms are considered to be the problem, making the identification of the problem... well a problem.
No. Hoofbeats usually means horses not zebras. Always eliminate the usual causes of the symptoms before chasing after any other possibilities. Quite often if you don't you'll wind up back at those dismissed usual causes that you dismissed.
I had a similar sittuation when I had Optix Prime enabled. I have a GTX 1060 with 6gb of VRAM. I rendered a huge Christmas Scene 6000x4000 scene with Optix enabled. And it processed fine. A few days ago I purchased Dog 8 and wanted to render Dog 8 with nothing else in the scene to a small 800x600 window. The render would would start on the gpu but then report there was a failure on the gpu and revert to the CPU. I tried rendering my Chirstmas Scene again to similar preview window and it worked. Tried DOg 8 again and the gpu failed.
I disabled Optix and the Dog 8 scene was fine. Tried several times with Optix disabled and was fine. Re-enabled Optix and gpu once again failed...